Self-locking snap-on collar for oil well operations

ABSTRACT

A thrust or stop-collar principally adapted for use on oil well drill pipes, sucker rods, guides, and similar equipment, combines a base of elastomeric or similar material with a novel spring insert. Configuration of the collar plus the effect of the specially constructed insert combine to give a very great bond between the shaft and the collar while permitting ready and economical installation and removal. An alternate embodiment provides a removable gripping ring inserted concentrically around the inner surface of the collar and disposed by geometry and construction to exert additional bond between the shaft and collar as further insurance against slipping while retaining the ease of installation and removal.

ilnited States Patent Collett [151 3,652,130 1 Mm'.2&1972

[s4] SELF-LOCKING SNAP-0N COLLAR FOR 01L WELL OPERATIONS [72] inventor:Charles H. Collett, PO. Box 411, Menlo Park, Calif. 94025 a [22] Filed:Apr. 23, 1970 [21] Appl.No.: 31,279

Related US. Application Data [63] Continuation-in-part of Ser. No.872,229, Oct. 29,

1969, abandoned.

[52] US. Cl. ..308/4 A [51] lnt.Cl. ..F16c 17/00 [58] Field ofSearch..30 8/4 A, 4; 285/45, 235, 236,

, [56] References Cited UNITED STATES PATENTS Primary Examiner-Martin P.Schwadron Assistant Examiner-Ronald H. Lazarus Attorney-Alfons Puishes[5 7] ABSTRACT A thrust or stop-collar principally adapted for use onoil well drill pipes, sucker rods, guides, and similar equipment,combines a base of elastomeric or similar material with a novel springinsert. Configuration of the collar plus the effect of the speciallyconstructed insert combine to give a very great bond between the shaftand the collar while permitting ready and economical installation andremoval. An alternate embodiment provides a removable gripping ringinserted concentrically around the inner surface of the collar anddisposed by geometry and construction to exert additional bond betweenthe shaft and collar as further insurance against slipping whileretaining the ease of installation and removal.

7 Claims, 10 Drawing Figures SHEET 1 0F 4 Fig.3

INVENTOR. Charles H. Co /left Attorney PATENTED MR 2 8 I972 SHEET 3 0F 4INVENTOR. Charles H. Col/eff 7 K3 Attorney PAIENIEHMAR28 1972 3,652,138

SHEET Q [1F 4 INVENTOR.

Charles H. Col/gr! Attorney SELF-LOCKING SNAP-ON COLLAR FOR OIlL WELLOPERATIONS This application is a continuation-in-part of my co-pendingapplication Ser. No. 872,229 filed Oct. 29, 1969, now abandoned.

BACKGROUND OF THE INVENTION No. 3,490,526 and Ser. No. 810,136 filedMar. 25, 1969, now I Pat. No. 3,528,499. These problems are, in general,brought about by the extremely high temperatures and pressuresencountered and by the very high loads and stresses resulting fromoperating at great depths.

In the case of sucker rods, various types of guides have been devised toattempt to obtain proper operation of the rod in the tube. These havebeen developed so as to facilitate the up and down motion of the rod inthe tube, prevent binding and jamming, undue friction, wear, breakage,especially where the well bore itself is quite crooked, as is often thecase.

In the case of drill pipes, similar problems are encountered. Protectorsof various types of construction have been devised of facilitate therotation of the pipe and its descent into the well. These in general actas bushings and may be fixedly positioned on the pipe and rotate with itor be loosely positioned thereon and permit of limited motion in anaxial direction, as well'as floating or not rotating with'the pipe whilethe latter is rotating and descending into'the well.

Illustrations of the former type of protector are seen in my U.S. Pat.Nos. 3,019,063 and 3,094,360. Illustrations of the latter type are seenin U.S. Pat. No. 3,397,017 to Grant and in my co-pending applicationSer. No. 810,136, mentioned above.

The problems have been attacked also by the use of different materialsfor the protectors and guides, such as special elastomeric materials andvarious plastic materials with or without the combination of metallicelements of various configurations.

In every instance, whether the protector or guide is stationary, orwhether it is movable or floating, there is the problem of confining itto its fixed position or confining its travel within fixed andpredetermined limits. This is very important in that the guide orprotector must not travel along the rod or tube to points where it isnot needed and especially over enlarged portions of the rod or pipewhere it would expand and cause jamming.

To protect against the latter condition, various types of stop-collarshave been used. These have comprised essentially, thrust collars similarto those used on rotating shafts of machinery, fixedly positioned on therod or pipe by means of set screws or clamps and located at the desiredpositions. Illustrations of these are seen on my U.S. Pat. No. 3,094,360and Grants U.S. Pat. No. 3,397,017.

The problem of maintaining these stop-collars at the predeterminedlocations under the extreme conditions existing in oil well operationshas been a tremendous one for many years.

The loads existing on a drill pipe may be as high as 40 tons or more.The tensile stress on the pipe wall, of course, causes it to elongateand consequently causes the outside circumference to decrease or shrink.Both of these effects combine to cause the stop-collars to loosen on thepipe or rod and shift position, thereby nullifying their value and, infact, increasing the hazard to the well.

Another problem which aggravates the condition and is well known tothose skilled in the art of oil field operations, is that any device ofthis class, especially pipe protectors and thrust or stop-collars, mustbe so constructed that they could be quickly and economically applied tothe pipe and easily removed from the pipe in the field with a minimumexpenditure of time and labor.

SUMMARY or THE INVENTION I have discovered that by utilizing astop-collar of a novel construction comprising an elastomeric or similarmaterial in combination with a metallic component, in itself having anumber of novel features, I am able to solve the operating problemsoutlined above. I have discovered further that I am able to construct mynovel collar so as to make it readily and easily applied to an oil welldrill pipe, sucker rod, or other component, and quickly removedtherefrom. l have discovered still further that my novel constructionproduces unusual and unexpected results insofar as adherence by mycollar to a drill pipe or other well components are concerned, as wellas resistance to undesirable movement while preserving the integrity ofthe well.

More specifically, l utilize a stop-collar which is basically of anelastomeric or similar material. Imbedded in the base I employ ametallic insert of spring steel, or similar material. My insert isspecially constructed to effect a tight and positive bond with the basematerial of the collar and at the same time provide a positive contactwith the drill pipe or rod.

I further employ a special configuration of the internal surface of mycollar which multiplies the effectiveness of the bond between my collarand the pipe, or other element, while at the same time providing forproper circulation of the drilling mud or oil. Actually, the latterfeature was at first introduced to provide for adequate circulation, butI have discovered that it produced an unusual and unexpected resultinsofar as strong contact between the collar and pipe as described morefully below.

I have discovered that by using the basic construction of my invention Iam able, with the aid of comparatively simple tools, to effectthe rapidand economical application of my collar to an oil well component and itsremoval therefrom. Part of this is due to the basic simplicityvof myinvention as compared with previous devices.

Finally, I have discovered further that by adding a concentric removablegripping ring on the interior surface of my collar and in contact withthe pipe, I am able to obtain still greater adherence between the collarand the pipe and still be able to rapidly and simply remove the collarfrom the pipe and also to replace the removable gripping ring.

All of the foregoing will be evident to those skilled in the art fromthe detailed description which follows.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal section through atypical well showing drill pipe, protector, and stop-collars.

FIG. 2 is a partial elevation of the upper end of one joint of a drillpipe showing location of protectors and stop-collars in position.

FIG. 3 is an isometric view of the stop-collar of my invention isunlatched position.

FIG. 4 is a metallic spring insert of my stop-collar, showing bondingholes, dogs, latch slot, and tongue.

FIG. 5 is a cross-section through a drill pipe showing the method ofapplication of my collar.

FIG. 6 is an exploded isometric view of an alternate embodiment of myinvention employing a removable gripping ring insert.

FIG. 7 is an isometric view of my collar showing the provisions forutilizing the gripping ring.

FIG. 8 is an end view of the removable gripping ring.

FIG. 9 is an end view of a corrugated backing spring which I may useinstead of my removable gripping ring.

FIG. 10 is a cross-section through my collar showing the relationshipbetween my collar and gripping ring.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings andparticularly first to FIG. 1, there is seen the shaft of a drill pipe orsucker rod 1. Actually, what is shown in FIG. 1 is a drill pipe, but itwill be evident to those skilled in the art that this description couldbe readily applied to a sucker rod as well, with certain obviousmodifications. In the case of a drill pipe, there is a hollow centralchannel 2 which is concentric with the outside diameter of the pipe andprovides a conduit for the circulation of drilling mud. To facilitatethe junction of successive lengths of drill pipe, the latter areequipped with tapered sections 3 to enlarge the diameter and provide fora threaded section 4 at each end, one being a male type and the other afemale type connecting element. The bore tube or well casing 5 is ofsuitable metallic construction well known to those skilled in the art.

A protector 6 is disposed to ride on the outside diameter of the drillpipe 1 and bear against the inside diameter of the bore tube 5. Theprotector may be of any particular construction known to the art, suchas that described in my application Ser. No. 801,136. It may be ofplastic, elastomeric, or even metallic construction and is equipped witha locking pin 7 and liquid circulating grooves 9 in the embodiment shownon FIG. 1. My stop-collars 11 equipped with latching holes 12 arepositioned on drill pipe 1 in a predetermined spaced relation with theprotector in a manner described more fully below.

The actual relative position of the protector, and the stopcollars onthe drill pipe will vary with the condition of the well. In a typicalsituation the first or upper stop-collar may be located approximately 3feet from one end of the drill tube section with a space ofapproximately 2 inches between the stop-collars and the protector,permitting the corresponding amount of travel up and down by theprotector. The actual overall length of drill pipe sections may be 30feet or more.

In the case of particularly crooked or difficult wells, I may use twoprotectors which may be spaced approximately 3 inches apart, between oneset of stop-collars. This embodiment is shown in FIG. 2. Here my twoprotectors 6 are equipped with locking pins 7 and interlocking joint 8,which facilitates snapping of the protector, usually of elastomeric orplastic material, around the outside of drill pipe 1. In this embodimentinner circulating grooves are seen at 10. The other elements andcomponents are as described for FIG. 1.

Referring now more particularly to FIG. 3, there is seen my stop-collar11 with its latching holes 12. The body of the stopcollar is comprisedprincipally of an elastomeric material in which are provided axialgrooves 14, the latter performing combined function of providing forcirculation of liquid and the formation of contact pads on the innersurface of the collar 15, which are disposed to bear against the outsidesurface of the drill tube. Imbedded concentrically in the elastomericmaterial 13 is a metallic insert 16 which may be of spring steel orsimilar material. Near one end of the open collar 11 there is located aslot 17 which is in alignment with a tongue 18 positioned on theopposite end of the collar. Positioned on the metallic insert andprotruding through he interior surface of the elastomeric material 13are are punched out bonding tabs or dogs 20. The latter are best seen onFIG. 4 to which reference should now be had.

The metallic insert, which may be of any springy material,

but I prefer to use a good grade of spring steel, is equipped with atleast two rows of bonding holes 19 suitably spaced around thecircumference of the inert 16. These serve to strengthen the physicalbond between the metallic insert 16 and the elastomeric material 13,which may be accomplished by any suitable method known to the art.

The bonding tabs or dogs 20 are preferably punched out of the body ofthe metallic insert 16 in the form of protruding lips of roughlysemi-circular configuration and disposed to point alternately towardopposite ends of the collar insert 16. They are likewise disposed toprotrude beyond the inside surface of elastomeric material 13 asmentioned above and bite into the drill tube as described below. Thesetabs or dogs serve the additional purpose of strengthening the bondbetween the metallic insert 16 and the elastomeric material 13.

Seen also on FIG. 4 is slot 17 and tongue 18 which form an integral partof the metallic insert 16 and combine to form a latching mechanism forthe collar. The function of all of the foregoing elements and theirinter-relationship may be understood from a study of FIG. 5 to whichreference should now be had.

In addition to illustrating the method of application or installation ofmy stop-collar on a drill pipe, FIG. 5 shows another view of the variouselements of my invention described above. To install my collar I firstopen it manually a sufficient distance to permit spring it over theoutside circumference of drill pipe 1 in a radial direction somewherenear the desired final location on the drill pipe with reference to thepipe itself, as described above. I then may slide it axially to itsfinal position on the pipe, manually. I then employ my specialinstallation tool 21. This comprises essentially a pair of tongs havinga high mechanical advantage or leverage ratio and equipped with latchingpins 22. The latching tool 21 is open sufficiently so that latching pins22 may line up with outer latching holes 12. The pins 22 are theninserted in the corresponding holes 12 and the handles of tool 21brought together which acts to compress the entire collar 11. This iscontinued until tongue 18 is opposite slot 17 into which it then springsdue to the inherent springiness of my collar. At this point the latchpin 22, which is closest to tongue 18 will be opposite center latchinghole 12, on my collar, thereby providing clearance for the part oflatching pin 22 which protrudes through the interior of metallic insert12 and facilitates the completion of the joining of the collar aroundthe pipe.

Referring again to FIG. 4 there is seen a section of metallic insert 16extending from its inner end as far as slot 17 and designated as 16a.This may be referred to as my land. The inherent springy nature of myinsert 16 as hereinabove set forth causes my tongue 18 to ride on thesurface of land 16a as the insert is being compressed by the action oftool 21. When tongue 18 riding on the land comes opposite to slot 17 itautomatically springs into slot 17. Because of its acute angleconfiguration described above, tongue 18 provides a positive engagementof my collar. I may round off the engaging edge of slot 17 to facilitatethis engagement. In my event, it is evident that I may rapidly effectthis engagement by movement of my tongue 18 only along its owncylindrical surface in a circumferential direction and need not employany special tool or other means to effect axial movement of my tongue 18in order to effect its engagement with slot 17.

In other words, engagement between the tongue and slot of my inventionmay be effected by movement in a single circular plane only, which is oftremendous advantage in view of the high pressures and stressesencountered which make latching and unlatching devices of this typeexceedingly difficult.

The use of this construction and method of installation produces acombination of effects, the result of which are to provide an unusuallystrong bond or adherence between my collar and the drill tube.

In addition to the holding effect resulting from the positive action ofthe digs 20, I obtain an unusual and highly effective bonding actionbetween the inner surface of my collar and the outer surface of thepipe. This is brought about by the effect of the pads 15 which areformed as a result of the circulation grooves 14 as described above.These pads act individually because of the resilient nature of thematerial under the action of the spring tension of the metal insert 12.Thus any irregularity, deformation, or entry of foreign matter betweenthe tube and inner surface of the collar is automatically compensatedfor, which would not be the case if this inner surface were continuous.In this manner, a very unusual and unexpected increase in bond betweencollar and tube results.

To provide for still more positive contact between my collar and therotating pipe I may install my collar on the pipe so that the directionof rotation of the pipe tends to increase the strength of engagementbetween my slot 17 and tongue 18. Thus as shown in FIG. 3 my drill pipewould be rotating in a clockwise direction when viewed from the top ofthe figure. To insure this I may mark the direction of rotation at anappropriate place on my collar and place the word on the upper edge ofthe collar thus assuring installation of my collar on the pipe to obtainthe greatest advantage from my construction.

Of course, I proportion the inside diameter of my collar in relation tothe outside diameter of the drill pipe in a predetermined relationshipdepending on the nature of the material which I use for my elastomericcover and in proportion to its known resilience. This will vary with heparticular material used, but will not affect the basic nature of thestrong bond which results from my construction and method andinstallation.

It should now be evident to those skilled in he art that in addition tothe high bond which I obtain, my collar may be very readily and quicklyinstalled in the field and very easily removed. In fact, the removal maybe effected by merely placing a screw driver between the overlappingportions of the collar at a point close to the slot 17 and tongue 18 andgiving it a slight twist, thereby causing the collar to spring off. Myconstruction and installation, it is evident, eliminates the use of setscrews, pins, or other additional components to effect the desiredresult.

As stated above, I have described an installation applying particularlyto a drill pipe. It should now be evident also that similar installationof my collar may be made on a sucker rod. When located on a sucker rodclose to its upset portion or close to the coupling, my collar may actas a protector in itself. This is particularly advantageous inprotecting the well tubing as the rod moves or heaves during operationand especially so in a particularly crooked well. I have also found thatmy construction and method of installation may be used to position acentralizer on a well casing as a protector itself or as asub-stabilizer, as for example, on a Kelly bar. In all theseapplications, the construction of my collar and its method ofinstallation are essentially like those described above for a drillpipe.

Attention should now be had to figs. 6 through which illustrate analternate and improved embodiment over those disclosed above. In thisembodiment I provide a concentric circular groove 21 in the body of mycollar 13. I then provide a new ring insert 22 best seen on FIG. 8 whichis disposed to fit 1 inside groove 21 and is equipped with verticalcirculation grooves 23 which are disposed to coincide with the oldgrooves 14 in the basic collar.

Instead of my ring insert 22 I may use a spring or corrugated member 25,best seen on FIG. 9, inserted in groove 21. This ring, like my ring 22,is disposed to bear against and apply pressure to the outer surface ofthe drill pipe. When using my ring 22 I may provide it with chamferededges 26 to comprise a dovetail construction between basic ring 13 andinsert 22 which may be best seen on FIG. 10.

For the material for my removable insert 22 I may use any suitableelastomeric or plastic material depending upon the particular specialapplication. My corrugated member 25 may be of any metal or otherresilient material and may be coated with a plastic or elastomericmaterial. I have discovered, for example, that differently fabricatedmaterials have different gripping power as distinguished from generallymolded materials which have good wearing properties.

As thus constructed, my gripping ring provides a very greatly increasedresistance to motion of the collar in an axial direction and greatlyimproves its gripping action. As thus constructed also, my gripping ringmay be readily removable and replaced with rings having a smaller insidediameter to compensate for pipe wear.

The grooves in an axial direction 23, of course, preserve thecirculating features of my basic disclosure described above.

I claim:

I. In a split collar of generally cylindrical configuration for oil welldrilling equipment and having a body of elastomeric material, theimprovement comprising:

a spring member of generally cylindrical configuration embeddedconcentrically in said body;

a slot through said body and said spring member positioned near thefirst end of said collar;

that portion of said body external to said spring member terminating ata point adjacent to said slot thereby forming an exposed outer surfaceof said spring member from said slot to said first end of said collar;

a tongue positioned on the second end of said spring member in alignmentwith said slot, forming an acute angle with the tangent to said springmember, protruding inwardly through said body and disposed to bearagainst 5 said exposed outer surface of said spring member;

means associated with said spring member for tightening said collararound a cylindrical shaft and simultaneously causing said tongue toride against said exposed outer surface until said tongue springs intosaid slot;

whereby said collar is held in a tightly fixed position around andagainst said shaft;

said means for tightening being further characterized by effecting theengagement between said tongue and said slot through movement of saidtongue in a single circular plane.

2. A split collar of generally cylindrical configuration for use withoil well drilling equipment and employing a spring member imbedded in abody of elastomeric material, said collar being characterized by:

means for tightening said collar around a cylindrical shaft; positivetongue and slot means for engaging said collar around said shaft in atightened position; engaging means positioned on the inner surface ofsaid collar, said engaging means being disposed for contact against saidshaft to prevent axial movement of said collar relative to said shaft;said spring member in said collar having an area positioned on its outercylindrical surface adjacent to and in cooperative relation with saidslot and said tongue; whereby the engagement of said collar around saidshaft may be effected by movement of said tightening means in a circulardirection only;

said spring member in said collar having an exposed area on its outercylindrical surface encompassing said slot;

said tongue means being disposed for riding against said exposed areawhile under the action of said tightening means;

whereby the engagement between said tongue and said slot means and saidcollar around said shaft is effected by movement of said tongue meansrelative to said slot means in a circular direction only.

3. A split collar of generally cylindrical configuration for oil welldrilling equipment comprising:

a body of elastomeric material;

a spring member in cooperative relation with said body;

axial grooves on the inside surface of said collar defining a pluralityof parallel contact surfaces;

a plurality of holes through said spring member and around thecircumferences thereof;

a slot positioned near the first end of said split collar;

a tongue positioned near the opposite end of said split collar and inalignment with said slot;

means associated with said spring member for tightening said collararound said shaft and causing said tongue to be inserted in said slot;

a circular groove around the inner surfaces of said collar;

a removable ring adapted for insertion in said grooves.

4. The collar of claim 3 in which said removable ring comprises thecombination of a springy material and an elastomeric outer covering.

5. The device of claim 1 in which cooperating opposed ends of saidspring member adjacent to said slot and to said tongue compriseoverlapping cylindrical surfaces;

said ends of said surfaces being exposed on their axial edges;

whereby the disengagement between said slot and said tongue may bereadily effected by insertion of disengaging means between saidoverlapping cylindrical surfaces in an axial direction only.

6. The device of claim 1 in which said acute angle formed between saidtongue and spring member comprises in addition 75 a circular arc betweensaid tongue and said spring member.

7. The device of claim 1 in which said means for tightening said collarcomprises a pair of oppositely spaced holes one of said holes beingpositioned adjacent said slot and the other positioned adjacent saidtongue said holes being suitably reinforced to prevent rupture of saidspring member while being 5 subject to the action of said tighteningmeans.

1. In a split collar of generally cylindrical configuration for oil welldrilling equipment and having a body of elastomeric material, theimprovement comprising: a spring member of generally cylindricalconfiguration embedded concentrically in said body; a slot through saidbody and said spring member positioned near the first end of saidcollar; that portion of said body external to said spring memberterminating at a point adjacent to said slot thereby forming an exposedouter surface of said spring member from said slot to said first end ofsaid collar; a tongue positioned on the second end of said spring memberin alignment with said slot, forming an acute angle with the tangent tosaid spring member, protruding inwardly through said body and disposedto bear against said exposed outer surface of said spring member; meansassociated with said spring member for tightening said collar around acylindrical shaft and simultaneously causing said tongue to ride againstsaid exposed outer surface until said tongue springs into said slot;whereby said collar is held in a tightly fixed position around andagainst said shaft; said means for tightening being furthercharacterized by effecting the engagement between said tongue and saidslot through movement of said tongue in a single circular plane.
 2. Asplit collar of generally cylindrical configuration for use with oilwell drilling equipment and employing a spring member imbedded in a bodyof elastomeric material, said collar being characterized by: means fortightening said collar around a cylindrical shaft; positive tongue andslot means for engaging said collar around said shaft in a tightenedposition; engaging means positioned on the inner surface of said collar,said engaging means being disposed for contact against said shaft toprevent axial movement of said collar relative to said shaft; saidspring member in said collar having an area positioned on its outercylindrical surface adjacent to anD in cooperative relation with saidslot and said tongue; whereby the engagement of said collar around saidshaft may be effected by movement of said tightening means in a circulardirection only; said spring member in said collar having an exposed areaon its outer cylindrical surface encompassing said slot; said tonguemeans being disposed for riding against said exposed area while underthe action of said tightening means; whereby the engagement between saidtongue and said slot means and said collar around said shaft is effectedby movement of said tongue means relative to said slot means in acircular direction only.
 3. A split collar of generally cylindricalconfiguration for oil well drilling equipment comprising: a body ofelastomeric material; a spring member in cooperative relation with saidbody; axial grooves on the inside surface of said collar defining aplurality of parallel contact surfaces; a plurality of holes throughsaid spring member and around the circumferences thereof; a slotpositioned near the first end of said split collar; a tongue positionednear the opposite end of said split collar and in alignment with saidslot; means associated with said spring member for tightening saidcollar around said shaft and causing said tongue to be inserted in saidslot; a circular groove around the inner surface of said collar; aremovable ring adapted for insertion in said grooves.
 4. The collar ofclaim 3 in which said removable ring comprises the combination of aspringy material and an elastomeric outer covering.
 5. The device ofclaim 1 in which cooperating opposed ends of said spring member adjacentto said slot and to said tongue comprise overlapping cylindricalsurfaces; said ends of said surfaces being exposed on their axial edges;whereby the disengagement between said slot and said tongue may bereadily effected by insertion of disengaging means between saidoverlapping cylindrical surfaces in an axial direction only.
 6. Thedevice of claim 1 in which said acute angle formed between said tongueand spring member comprises in addition a circular arc between saidtongue and said spring member.
 7. The device of claim 1 in which saidmeans for tightening said collar comprises a pair of oppositely spacedholes one of said holes being positioned adjacent said slot and theother positioned adjacent said tongue said holes being suitablyreinforced to prevent rupture of said spring member while being subjectto the action of said tightening means.